IB/core: Add timestamp_mask and hca_core_clock to query_device

In order to expose timestamp we need to expose two new attributes in
query_device to be used for CQ completion time-stamping:

timestamp_mask - how many bits are valid in the timestamp, where timestamp
values could be 64bits the most.

hca_core_clock - timestamp is given in HW cycles, the frequency in KHZ units
of the HCA, necessary in order to convert cycles to seconds.

This is added both to ib_query_device and its respective uverbs counterpart.

Signed-off-by: Matan Barak <matanb@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>